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MG Midget and Sprite Technical - Engine failure diagnosis

So,

Big ends had gone, only bother taking one half of number 1 off before I realised there was no white metal on it at all and it was down to the copper... consequently the crank needs regrinding... so I put it back in and will have to have the engine out to send the crank away.

Anyone got any good recommendation for London grinders? I've got a couple of places in mind but any suggestions welcomed.


C L Carter

Incidentally, does anyone know what the correct journal diameters were - so I can work out if its been ground before.
C L Carter

look at the back of the bearing.
Size should be marked there
Onno K

Look on the back of the bearing shell you have removed. It will either have a number, 10, 20 etc or STD for standard. If there is no marking, then it is probably just standard.

You now need to try and track down why the bearing failed.

Oh, and order some new crank thrust washer too.
What are the mains like?
Guy

Nothing but a serial number on the back of the shell

Didn't have the mains off, no point - engine has to come out now so I'll wait until I get chance to do that.

Yes. I do need to know why bearing failed. However, I think it was possibly just age and that it has been going for ages... they could be original! 76k miles is a lot for a set of bearings.
C L Carter

Not as a result of overheating then ?
Guy

Guy you are a one :)

Christian,
I know all this engine stuff is manly, macho, butch, sexy stuff but really an engine is not that important in car but the brake system is most important

the engine rumbling on your tour is unfortunate especially as you'd part prepared it for the tour

now I know you (partly) know this - brakes should be in good condition before you go places like Hardnott and Wrynose passes - I was surprised you knew you'd only partly sorted your brakes and still went to such places - I thought you'd fully sorted your brakes before you went

full marks for sorting your brakes first on your return before playing with the engine but always remember that order - brake systems first and engine well down the list after brakes, tyres, suspension, seeing and been seen (lights and windows)

when you lift the bonnet your first though should be brake reservoir not dipstick i.e. brakes not engine
Nigel Atkins

I think the big ends went completely... then I lost oil pressure because of it... and thats what caused the overheating.

I can't think what else could be wrong with the car, I've been through everything else... Unless the new head gasket went... which I'll find out about shortly anyway... the oil wasn't mayonaissey... but it was a bit different - I think because its full of gritty bits of bearing.


Also, I found a tiny piece of what looks like cast iron in the sump... although it could be a bit of piston ring... I hope so anyway.


C L Carter

this car sounds coal fired :)

HGF, or the start of HGF, is always easier to spot with hindsight

the many and various symptoms don't always appear or are obvious at the time and if they do not straight away
Nigel Atkins

Christian,
Does your bit of debris stick to a magnet?
Difficult to tell from a photo, but somehow it doesn't look the right texture for a bit of piston ring. can't think what else though.!
Guy

perhaps put something in photo to give scale like a measure
Nigel Atkins

Yes, will check all that tomorrow when I'm back in the garage. As for size, its about an 1/8th thick by about 3/16 wide by about 1/4 long... but will photograph it by a rule tomorrow and check whether its magnetic. I don't think its coal - hard to think how it could get in the sump if it were, and especially as i'd just cleaned the head 2 weeks before.

C L Carter

got my head skimmed and new valve seats for unleaded by a firm in surbiton. . . .cant think of there name, but i will have a hunt through some receipts for you
p bentley

Col Carpenter at Southern Rebore Services. Col owns a couple of midgets.
A Anstead

Thanks for suggestions - but I've already had it done... Got it done at ROE engineering in Fleet. £75 - 4 days. Very happy with that. Recommended by a colleague.

So following on, if people are still interested - that lump is 5mm in its longest direction and is non magnetic... Perhaps it is coal? but how would it get into the sump?

On another point. Oil pumps. I've check my oil pump for clearance and its within tolerance - but its horribly scored... presumably cos its picked up debris and grit from the bearings. See photo. Does anyone have a spare pump they are willing to sell?

C


C L Carter

Always fit a new oil pump. A series pumps, especially the 948/1098 ones, are of marginal capacity and they are cheap compared with the consequences of not enough oil. Some of the new pumps on the market have a higher capacity than the original, which is a definite plus.
Paul Walbran

CL Carter. . .i may have a spare and am down the road to you in surrey (chertsey) do you want me to look or are you sorted now ??
p bentley

Christians car is a 1500 not an A series is it not?

Malcolm
Malcolm Le Chevalier

Same applies whether 1500 or A series; its well worth the £50 or so to just fit a new pump
Guy

Mr Bentley, Thanks for your offer - I haven't sorted a pump yet, but if you have one for a 1500 with good tolerances then yes I'd be very interested. Thank you very much.

Drop me an email on carter dot christian at g mail dot com


Guy, you can just keep adding to that though until you've spent thousands on the car. I'm already way past the point of economic return, but perhaps I might have to grin and bear it again and spend the £65
C L Carter

Christian,
I know it is easy once the catalogue is open in front of you (or online)!! But I am extremely tight-fisted and wouldn't go spending money unnecessarily either! Other stuff I might well make do with, but to me, a decent oil pump on a 1500 is essential spending
Guy

Yeah - you're right. But this thing keeps eating my money. Today I foundout I need a new camshaft!

I think I'll buy a new lobe kit for £20... cos the main body isn't that scored.

C L Carter

What does a LOBE KIT consist of. Nosey minds want to know.
darnoc31

The inner and out lobe which you fit to your existing pump body.

C L Carter

This thread was discussed between 22/04/2012 and 05/05/2012

MG Midget and Sprite Technical index

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